Example embodiments relate generally to cleaning compositions, related cleaning methods for a semiconductor substrate, and methods of manufacturing a semiconductor device using same. More particularly, Example embodiments relate to cleaning compositions removing impurities from a semiconductor substrate having a metal structure in a single-wafer cleaning process, related methods of cleaning a semiconductor substrate and methods of manufacturing a semiconductor device using same.
The fabrication of semiconductor devices on a semiconductor substrate routinely involves the deposition of conductive material layers, as well as their patterning and etching. The resulting “conductive elements” (e.g., signal lines and other wiring, electrode structures, etc.) are used to conduct electricity between various circuits. Accordingly, metal and metal alloys (e.g., tungsten, aluminum, etc., and collectively referred to as “metal”) are used.
A conductive element may be formed from a constituent material layer using a dry etching process to partially remove a conductive layer using a photoresist pattern as an etching mask, along with an ashing process and/or a stripping process to remove the photoresist pattern. When the conductive element is formed on a substrate using a dry etching, ashing, and/or stripping processes, however, impurities remain on the conductive element and/or the underlying substrate or associated material layer(s). Examples of such residual impurities include etching residues, organic residues, oxide residues, metallic residues and combinations thereof. These residual impurities may alter the electrical resistance of a semiconductor device incorporating the conductive element, or generate an electrical short between adjacent conductive elements. Thus, a cleaning composition capable of removing residual impurities from conductive elements and/or the substrate is required in order to ensure the reliability of the semiconductor device.
Conventional cleaning solutions such as APM (standard cleaning solution, SC-1) or SPM (sulfuric acid stripper) may corrode certain types of metal (e.g., tungsten) when used in a cleaning process to remove residual impurities. Thus, conventional cleaning solutions may not be used to clean a substrate having exposed metal element(s).
Substrates having exposed metal elements are conventionally cleaned using an organic stripper comprising an organic solvent. The organic stripper does not severely corrode the exposed metal, but it may fail to adequately remove residual impurities from the metal elements and/or the substrate.
During a cleaning process, residual impurities may actually be dispersed through the applied cleaning composition as suspended particles. Further, a portion of the metallic residual impurities may dissolve in the cleaning composition and form metal ions. As the number of semiconductor substrates (or wafers) to-be-cleaned during a cleaning process increases, so too does the overall duration of the cleaning process. As the duration of an applied cleaning process increases, the quantity of suspended (and potentially contaminating) particles and/or dissolved metal ions in the cleaning composition also increases. Suspended particles and dissolved metal ions may then be transferred from one wafer to another during a batch cleaning process. At a minimum, such contaminated wafers require re-cleaning and thus reduce the productivity of the overall semiconductor fabrication process. Worse yet, contaminated wafers make yield inoperable or impaired semiconductor devices.
Newer conventional organic cleaning compositions exhibiting improved effectiveness have been developed. However, organic cleaning compositions, while rapidly removing organic impurities (e.g., photoresist residue) exhibit relatively poor performance in removing fine particles and/or residual metallic impurities. Many related conventional cleaning processes for removing impurities must be performed by immersing a plurality of wafers into a bath for some time period. In such cleaning processes, fine particles or metallic impurities readily disperse in the bath and may contaminate the wafers. Additionally, organic cleaning compositions may include volatile organic components that contaminate a working space in a semiconductor fabrication facility.